Availability throughout the world of proteins of animal origin is not sufficient to cover needs. Almost one-third of the world's population suffers from malnutrition due to protein deficiency. For under-developed regions it is estimated that in the year 2000, proteins will have to be available in quantities from 4 to 7 times greater than those required in 1968.
The quantitative problem is doubled by an economic problem: it is necessary to have sufficient, available protein at very low cost.
The soya bean, which can be cultivated and produced intensively, fulfils the desired quantitative and economic criteria. The soya bean, or soya, is rich in protein of well balanced amino acids composition, with the exception of a slight deficiency in methionine which can be corrected easily and cheaply. Its lysine content (approximately 6g per 16g nitrogen) is the highest in the vegetable kingdom. Soya contains almost as much lysine as eggs.
The use of soya, from which the oil has been removed, as a source of protein for feeding animals has undergone considerable development in the last 20 years. More than 5 million tons of soya cake per year are now used in Common Market countries.
For feeding humans, various protein concentrates have been extracted from soya, most frequently at a high cost (texturised protein for example).
The contribution which soya has to make in economically reducing protein deficiency throughout the world still remains to be perfected.
Whole raw soya or soya from which the oil has been removed is poorly tolerated by the human system; it causes insufficient growth and serious physiological disorders.
Soya contains various known and unknown factors, which prevent its assimilation by the digestive system, e.g. anti-enzymatic substances (anti-trypsin, anti-alpha-chymotrypsin.
Industrial treatments, particularly of the thermal type, make it possible to improve the nutritional quality of the soya by deactivating certain of these enzyme inhibitors (Annales de Zootechnie Vo.20 no. 1, 1971, Pages 11 to 89). This heated (toasted) soya incorporated in food for animals, after their weaning, no longer has the nutritional deficiencies of raw soya.
However, this soya thermally treated with a view to reducing its anti-proteasic activity, even if it ensures satisfactory growth without physiological disorders in the adolescent and adult human and animal system, does not ensure this in the young person or animal, above all at the ante-natal period.
The high cost of milk (particularly for suckling young ruminants), its declining production which will become rapidly deficient and the intolerance shown for it by many children are all inducements to search for a means to purify soya and make it acceptable for providing the protein requirements of young children and young animals in place of natural milk.
It has now been established that apart from proteasic inhibitors, the presence in soya of certain carbohydrates, particularly oligosaccharides (stachyose, raffinose, etc.), is responsible for digestive disorders (flatulance, diarrhoea, etc.) and for the imperfect assimilation of the soya proteins in young children and young animals, even when the soya has undergone heat treatment. These carbohydrates are mostly insoluble in water (less than 1 % are water soluble).
Oil-free purified soya concentrates have been produced on an industrial scale for several years and their carbohydrate content has been greatly reduced by the solvent action of an alcohol in a heated state. These products have been widely tested on infants and young calves; they have the required nutritional qualities without causing any of the digestive disorders aforedescribed (PROMOSOY, manufactured by Central Soya Inc., Decatur, Ill., U.S.A.). The effects of the action of certain enzymes on oligosaccharides such as are found in the seeds of leguminuous plants and in certain tubers are well known inter alia from the works of H. SUZUKI, Y. OZAWA and O. TANABE.
1963 "decomposition of raffinose by a-galactosidase of Actinomycetes". 1. Isolation and selection of strain. Nippon Nogei Kagaku Kaishi 37 : 673-679 ; PA1 1964 "Decomposition of raffinose in beet molasses by a-galactosidase". Hakko Kyokaishi 22 : 455-459 ; PA1 1966 "Studies on the decomposition of raffinose by a-galactosidase of Actinomycetes". IV. Characteristics of a-galactosidase and estimation of raffinose by the enzyme preparation. Agr. Biol.Chem.30 : 1039-1046.
U.S. Pat. No. 725,497 filed on Apr. 30th, 1968, now U.S. Pat. No. 3,632,346 by ROHM and HAAS Company consists of a process which makes it possible to decompose the oligosaccharides, present in certain foods which product flatulance by an enzymatic action, the principle of which has been described by the aforementioned authors. In this process, the sugars obtained after enzymatic degradation are not extracted and also the initial protein content of the soya is not increased.
A cattle food based on soya also exists which until now has been available on an experimental scale. The animal tolerance of this product is improved due to the decomposition of undigested carbohydrates by the enzymatic action on the soya of pectinases alone or associated with cellulases or hemicellulases. In this food, the sugars obtained after enzymatic degradation are not extracted and the initial protein content of the soya is not increased (Patent Application No. P1792142.5 of July 26th, 1968 in the German Federal Republic by ROHM/HAAS GmbH).
Soya bean is one of the richest vegetable products cultivated on this planet. Other vegetables exist, the seeds or roots of which have a less well balanced composition : they provide little protein and plenty of carbohydrates, especially in the form of starch.
In the family of leguminous plants large quantities of grain are used for human and animal feeding, such as broad beans, haricot beans, peas, lentils, etc. . .
In the family of the graminaceae, cereals such as wheat, rice, maize are used in considerable quantities.
In the family of the solanaceae the tuber of Solanum tuberosum, the potato, is universally consumed.
In the family of the euphorbiaceae, cassava (Manihot esculenta) provides a root which gives manioc or tapioca, a basic foodstuff of the countries of Africa, South America, etc. . .
Patents and publications referring to grain from leguminous plants, to cereals, to the potato, to manioc, describe methods of transformation of the carbohydrates, among them starch, by the action of various enzymes (examples : U.S. Pat. No. 3,782,964/1.1.74 -- Method of upgrading starch-containing crude gluten; U.S. Pat. No. 3,157,513/17.11.1964 -- Enzymatic treatment of cereal grains, Article by M. A. BUFFA which appeared in the "Revue des Industries Alimentaires et Agricoles"--Le Traitement exzymatique des farine de sevrage, 1968, II, p. 1477 describing enzymatic processing of flour from cereals and leguminous plants). The patents and publications, however, do not describe the elimination of the carbohydrates transformed by the action of the enzymes.